'use strict';
exports.byteLength = byteLength;
exports.toByteArray = toByteArray;
exports.fromByteArray = fromByteArray;
var lookup = [];
var revLookup = [];
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array;
var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
for (var i = 0, len = code.length; i < len; ++i) {
    lookup[i] = code[i];
    revLookup[code.charCodeAt(i)] = i;
}

// Support decoding URL-safe base64 strings, as Node.js does.
// See: https://en.wikipedia.org/wiki/Base64#URL_applications
revLookup['-'.charCodeAt(0)] = 62;
revLookup['_'.charCodeAt(0)] = 63;
function getLens(b64) {
    var len = b64.length;
    if (len % 4 > 0) {
        throw new Error('Invalid string. Length must be a multiple of 4');
    }

    // Trim off extra bytes after placeholder bytes are found
    // See: https://github.com/beatgammit/base64-js/issues/42
    var validLen = b64.indexOf('=');
    if (validLen === -1) {
        validLen = len;
    }
    var placeHoldersLen = validLen === len ? 0 : 4 - (validLen % 4);
    return [validLen, placeHoldersLen];
}

// base64 is 4/3 + up to two characters of the original data
function byteLength(b64) {
    var lens = getLens(b64);
    var validLen = lens[0];
    var placeHoldersLen = lens[1];
    return ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen;
}
function _byteLength(b64, validLen, placeHoldersLen) {
    return ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen;
}
function toByteArray(b64) {
    var tmp;
    var lens = getLens(b64);
    var validLen = lens[0];
    var placeHoldersLen = lens[1];
    var arr = new Arr(_byteLength(b64, validLen, placeHoldersLen));
    var curByte = 0;

    // if there are placeholders, only get up to the last complete 4 chars
    var len = placeHoldersLen > 0 ? validLen - 4 : validLen;
    for (var i = 0; i < len; i += 4) {
        tmp = (revLookup[b64.charCodeAt(i)] << 18) | (revLookup[b64.charCodeAt(i + 1)] << 12) | (revLookup[b64.charCodeAt(i + 2)] << 6) | revLookup[b64.charCodeAt(i + 3)];
        arr[curByte++] = (tmp >> 16) & 255;
        arr[curByte++] = (tmp >> 8) & 255;
        arr[curByte++] = tmp & 255;
    }
    if (placeHoldersLen === 2) {
        tmp = (revLookup[b64.charCodeAt(i)] << 2) | (revLookup[b64.charCodeAt(i + 1)] >> 4);
        arr[curByte++] = tmp & 255;
    }
    if (placeHoldersLen === 1) {
        tmp = (revLookup[b64.charCodeAt(i)] << 10) | (revLookup[b64.charCodeAt(i + 1)] << 4) | (revLookup[b64.charCodeAt(i + 2)] >> 2);
        arr[curByte++] = (tmp >> 8) & 255;
        arr[curByte++] = tmp & 255;
    }
    return arr;
}
function tripletToBase64(num) {
    return lookup[(num >> 18) & 63] + lookup[(num >> 12) & 63] + lookup[(num >> 6) & 63] + lookup[num & 63];
}
function encodeChunk(uint8, start, end) {
    var tmp;
    var output = [];
    for (var i = start; i < end; i += 3) {
        tmp = ((uint8[i] << 16) & 16711680) + ((uint8[i + 1] << 8) & 65280) + (uint8[i + 2] & 255);
        output.push(tripletToBase64(tmp));
    }
    return output.join('');
}
function fromByteArray(uint8) {
    var tmp;
    var len = uint8.length;
    var extraBytes = len % 3; // if we have 1 byte left, pad 2 bytes
    var parts = [];
    var maxChunkLength = 16383; // must be multiple of 3

    // go through the array every three bytes, we'll deal with trailing stuff later
    for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
        parts.push(encodeChunk(uint8, i, i + maxChunkLength > len2 ? len2 : i + maxChunkLength));
    }

    // pad the end with zeros, but make sure to not forget the extra bytes
    if (extraBytes === 1) {
        tmp = uint8[len - 1];
        parts.push(lookup[tmp >> 2] + lookup[(tmp << 4) & 63] + '==');
    } else if (extraBytes === 2) {
        tmp = (uint8[len - 2] << 8) + uint8[len - 1];
        parts.push(lookup[tmp >> 10] + lookup[(tmp >> 4) & 63] + lookup[(tmp << 2) & 63] + '=');
    }
    return parts.join('');
}
